Method of fabricating plow moldboards



Patented Dec. 15, 1953 UNITED STATES PATENT OFFICE METHOD OF FABRICATING PLOW MOLDBOARDS 2 Claims.

This invention relates to a method of fabricating plow moldboards and particularly to a-method of grinding the moldboard blank before the forming operation.

It has long been the practice to fabricate the moldboard of a plow or similar implements by first forming the blank to its desired finished shape by stamping or other suitable method whereupon the moldboard was then subjected to a heat treating process and finally the heat treated moldboard was then ground to produce the desired smooth finish thereon. While this procedure produces a moldboard which is acceptable, the cost of grinding the shaped moldboard has been excessive. The reason for such excessive cost is, of course, the compound curvature which is imparted to the moldboard in the manufacturing process, such curvature being necessary in order to properly turn the furrow slice. The more complicated the curvature of the moldboard, the more difficult it is to grind the landside surface of the moldboard after such moldboard has been completed. Admittedly, there have been machines developed to grind the landside surface of the moldboard mechanically, but such machines are relatively expensive as compared to a flat surface grinding machine. Furthermore, in grinding the finished moldboard on such machines, it is difficult to grind the working surface in a direction corresponding to the direction of land flow. Only by expensive hand grinding can the grain of the grinding be directed in the direction of the land flow across the moldboard.

It will therefore be quite evident that if the moldboard blank can be provided with an exceptionally smooth surface prior to its being formed into a moldboard, the manufacturing costs in processing the blank will be substantially reduced.

Accordingly, it is an object ofthis invention to provide an improved method in the manufacture of plow moldboards for simplifying the finishing of the working face of the moldboard.

Another object of this invention is to provide a method for fabricating the moldboard of an implement wherein the working surface of the moldboard is ground to an optimum finish prior to forming the blank to the final shape of the moldboard.

The specific nature of this invention, as well as other objects and advantages thereof will become apparent to those skilled in the art from the following detailed description in which is set forth several embodiments of this invention.

Briefly, this invention contemplates grinding a moldboard blank in a fiat condition so that the working surface of the moldboard is ground to a desired smoothness and in the general direction of the land flow. The ground surface is then plated or covered with suitable material to pre vent oxidation of such-surface during subsequent heating of the blank to permit forming thereof by any Well known pressing or forging operation. Alternatively, the blank may be formed to its final shape in a controlled atmosphere.

Accordingly, a blanket hardenable material is selected and is cut to the desired shape which after forming will produce a moldboard for a plow of the usual shape. The surface to form the landside surface of the moldboard is then finished to an optimum smoothness in the conventional surface grinder. The direction of the grinding is such as to have the grain of the grinding follow the general path of the land flow of the moldboard. By land fiow is meant the direction of flow of the-furrow slice across the moldboard as the plow is moved through the earth.

After the blank is ground to the desired smoothness on the landside surface, such surface is plated with-a coating of copper, chromium, or other oxidation resistant material. Alternatively, a suitable oxide preventive paint may be applied to the landside surface of the blank. At any rate, when the ground landside surface is so protected against oxidation, the blank is then heated in a furnace to an optimum temperature for forming the blank in a stamping machine,

forge, press, or other suitable press utilizing dies of the required shape to form the blank to the well known moldboard shape.

With the protective coating in the form of copper or chromium plating, or the oxide preventive paint on the landside surface of the now formed moldboard, the scaling or oxidation generally encountered on such surface when the blank is heated to a forging or shaping temperature is eliminated. Immediately upon forming the moldboard, the moldboard is then quenched to provide a desired hardness in the moldboard. Of course, if a relatively low temperature is employed during the shaping operation, the moldboard blank can be hardened prior to the grinding operation. Since only a thin layer or deposit of oxidation resistant material is applied, it is generally unnecessary to take special steps to remove such prior to using the moldboard. In fact, such material serves well to protect the moldboard surface from corrosion during the period between fabrication and purchase by the eventual user. A few hours use will quickly remove the oxidation resistant material, exposing the ground steel surface.

Alternatively, I also contemplate forming the ground blank in a controlled atmosphere whereby oxidation of the ground surface is substantially limited. This operation is effectively accomplished by utilizing a controlled atmosphere furnace for heating the blank and then transferring such blank to another controlled atmosphere wherein the forming apparatus is contained and therein forming the blank to the desired shape.

In the modification of the improved method for forming the moldboard, a hydraulically operated press utilizing suitable dies may be conveniently adapted for forming the heated blank to the desired moldboard shape. However, whatever type apparatus is utilized to form the blank to the desired shape, it is essential that the forming operation be performed in a controlled atmosphere wherein oxygen is substantially eliminated from contact with the landside surface of the blank in order to substantially eliminate oxidation of such surface.

Whichever of the methods are utilized as above described to prevent oxidation of the ground finished surface of the blank, it is obvious that the finishing operations of the moldboard are greatly simplified. It will be appreciated that the smoothing of the landside surface of the blank is cheaply and quickly achieved by the relatively simple operation of grinding in a surface grinder. Therein lies the greatest benefit of my improved method of fabricating plow moldboards, for not only can the landside surface of a moldboard be produced more economically and quickly, but the direction of the grain of the grinding can more readily be made to follow the land flow and thus produce a moldboard with improved scouring properties.

It will thus be apparent from the foregoing description that my improved method of fabricating plow moldboards will not only permit a reduction in the cost of processing the moldboards, but will produce a superior finish on the landside surface of the boldboard. It is further pointed out that the process is not limited only to the plow moldboard but may also be used in any similar application where a highly polished or smoother landside surface must be provided on an earth engaging tool which is required to work the earth. By way of example, cultivator sweeps and various types of points and other ground working elements which have relatively complicated compound curved earth engaging surfaces may be conveniently formed by my above described method to substantially reduce the cost of fabricating these elements It will, of course, be understood that various details of process may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim: 1

1. The method of fabricating plow moldboards which comprises the steps of finish grinding the working surface of the moldboard blank when the blank is in a planar configuration, the direction of said grinding being oriented with the expected direction of land flow along the finished moldboard, treating the ground surface with oxidation resisting material and subsequently forming the moldboard blank to the desired complex configuration.

2. The method of fabricating plow moldboards which comprises the steps of finish grinding the working surface of the moldboard blank when the blank is in a planar configuration, the direction of said grinding being oriented with the expected direction of land flow along the finished moldboard, subsequently hot forming the moldboard blank to the desired complex configuration, and protecting the ground working surface of said blank by the exclusion of gaseous oxygen from said surface during said hot forming.

UNITED STATES PATENTS Number Name Date 1,989,967 Bernstein Feb. 5, 1935 2,306,996 Altgelt Dec. 29, 1942 

